通过多个 STR 试剂盒比较和 Sanger 测序检测到 D5S818 连锁状态的变异。
Variants in linkage status at D5S818 detected by multiple STR kits comparison and Sanger sequencing.
机构信息
Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
Shanghai Hengping Judicial Expertise Center, Shanghai, 200070, China.
出版信息
Mol Genet Genomic Med. 2021 Sep;9(9):e1765. doi: 10.1002/mgg3.1765. Epub 2021 Jul 24.
BACKGROUND
D5S818 discrepancies have been reported in forensic parental testing due to null alleles. However, more cases may be ignored since proportional null alleles were missed without detection of heredity discrepancy between parents and offspring.
RESULTS
In this study, null allele 12 at D5S818 was detected by the PowerPlex 21 System with a higher occurrence rate on the basis of review on 2824 samples from the 1282 routine cases in Chinese Han population. Sequencing results revealed novel variant of guanine (G) into adenine (A) in the 7th [AGAT] repeats in the core repeat region accompanied by rs1187948322 in the samples with null allele 12.
CONCLUSIONS
Forensic STR typing may benefit from this discovery: (1) primer design of CE profiling system could be improved for sensitive population and (2) polymorphic information could be enriched for the accuracy and precision of NGS genotyping system. Peak area of D5S818 was also analyzed through different commercial STR kits. It is suggested that more attention should be paid on observed homozygosity with reduced peak area, especially for the samples from Chinese Han population.
背景
由于等位基因缺失，D5S818 差异已在法医亲子鉴定中报告。然而，由于未检测到父母和子女之间遗传差异，可能会忽略更多的案例，因为未检测到比例性等位基因缺失。
结果
在这项研究中，通过 PowerPlex 21 系统检测到 D5S818 中的等位基因 12，该等位基因缺失在基于对中国汉族人群 1282 例常规案例中的 2824 个样本的回顾中发生率较高。测序结果显示，在核心重复区域的第 7 个[AGAT]重复中，腺嘌呤（A）取代了鸟嘌呤（G），同时在存在等位基因 12 的样本中还存在 rs1187948322。
结论
本研究结果对法医 STR 分型具有重要意义：（1）CE 分析系统的引物设计可以针对特定人群进行改进；（2）通过增加多态性信息，提高 NGS 基因分型系统的准确性和精密度。通过不同商业 STR 试剂盒分析 D5S818 的峰面积。建议在观察到峰面积减少的纯合子个体时，特别是在来自中国汉族人群的样本中，应更加关注，以确保鉴定的准确性。
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